Throttle-free transmissionless hybrid vehicle

Abstract

In a high speed mode of operating and electric-gas hybrid car, the combustion engine is directly engaged to the wheels without a transmission and that vehicle speed is controlled without a throttle by electric generator loading of the engine.

1. A method of operating a hybrid vehicle having first and second motor-generators, a combustion engine, first and second wheels and an energy storage device for powering said motor-generators, said method comprising:
 operating said vehicle in a low-speed mode when vehicle speed is below a threshold speed, said low-speed mode comprising driving one of said motor-generators by said engine to charge said energy storage device while said engine is decoupled from said first and second wheels and while the other one of said motor-generators provides mechanical power to one of said wheels using electrical power from said one motor-generator or from said energy storage device; 
 when the vehicle speed exceeds said threshold, operating said vehicle in a high-speed mode comprising: 
 (a) engaging said engine through disengagable coupling to said first wheel, engaging a selected one of said motor-generators to one of said wheels or to said engine, propelling said vehicle with mechanical power from said engine while operating said selected one motor generator as an electric generator to charge said energy storage device; 
 (b) controlling the road speed of said vehicle by controlling a level of electric current generated by said selected one motor-generator so as to control a mechanical load of said selected one motor-generator on said engine. 
 
     
     
       2. The method of  claim 1  wherein controlling a level of electric current generated by said selected one motor-generator comprises controlling a current-controlling element connected with said selected one motor-generator. 
     
     
       3. The method of  claim 1  wherein said controlling a level of electric current generated by said selected one motor-generator comprises:
 sensing a user-selected vehicle speed control position; 
 determining from said control position whether the vehicle speed is to be increased or decreased; 
 decreasing said level of said electric current if said vehicle speed is to be increased; and 
 increasing said level of said electric current if said vehicle speed is to be decreased. 
 
     
     
       4. The method of  claim 3  wherein one of said decreasing and increasing corresponds to a change in said level of said electric current that is proportional to a difference between a recent control position and a previous control position. 
     
     
       5. The method of  claim 3  wherein one of said decreasing and increasing corresponds to a change in said level of said electric current that is a predetermined fixed amount. 
     
     
       6. The method of  claim 1  further comprising providing a first spline coupler between said engine and said one motor-generator and providing a second spline coupler between said one motor-generator and said first set of wheels. 
     
     
       7. The method of  claim 1  further comprising providing a first spline coupler between said engine and said first set of wheels, and providing a permanent connection between said one motor-generator and said second set of wheels. 
     
     
       8. The method of  claim 1  wherein operating said vehicle in said high speed mode comprises re-starting said engine, wherein restarting said engine comprises:
 disengaging said selected one motor-generator from said wheels, matching a shaft speed of said selected one motor-generator to a shaft speed of said engine and engaging said selected one motor-generator and said engine; 
 operating said selected one motor-generator as an electric motor with electricity from said energy storage device to start said engine; 
 upon said engine starting, operating said selected one motor-generator as an electric generator using mechanical power from said engine to charge said energy storage device so as to impose a mechanical load on said engine; and 
 matching a shaft speed of said engine to a shaft speed of a drive shaft of said vehicle by controlling the shaft speed of said engine and thereafter engaging said engine with said drive shaft. 
 
     
     
       9. The method of  claim 8  wherein controlling the shaft speed of said engine comprises controlling the magnitude of an electric current generated by said selected one motor-generator. 
     
     
       10. The method of  claim 9  wherein said controlling the magnitude of an electric current generated by said one selected motor generator comprises:
 sensing the speed of said drive shaft, sensing the shaft speed of said engine and detecting a difference in speed; 
 changing said magnitude of said electric current generated by said selected one motor-generator so as to reduce said difference. 
 
     
     
       11. The method of  claim 10  wherein said changing comprises increasing said magnitude if said engine shaft speed exceeds the speed of said drive shaft or decreasing said magnitude if said engine shaft speed is less than the speed of said drive shaft. 
     
     
       12. The method of  claim 1  further comprising operating said engine unthrottled. 
     
     
       13. A method of operating a hybrid vehicle having a first motor-generator coupled through a first disengagable spline to a drive shaft of the vehicle, a second motor-generator connected to said drive shaft or an other drive shaft of the vehicle, and a combustion engine coupled through a second disengagable spline to the first motor-generator, and an energy storage device, said method comprising:
 operating said vehicle in a low-speed mode when vehicle speed is below a threshold speed, said low-speed mode comprising driving one of said motor-generators by said engine to charge said energy storage device while said engine is disengaged from said drive shaft and while the other one of said motor-generators provides mechanical power to said one drive shaft or said other drive shaft using electrical power from said one motor-generator or from said energy storage device; 
 when the vehicle speed exceeds said threshold, operating said vehicle in a high-speed mode, said high speed mode comprising: 
 (a) engaging said engine to said one drive shaft or said other drive shaft through one or both of said first and second disengagable splines, propelling said vehicle with mechanical power from said engine while engaging a selected one of said motor-generators to said one or other drive shaft or to said engine and operating said selected one of said motor generators in a generator mode to charge said energy storage device; 
 (b) controlling the road speed of said vehicle by controlling a level of electric current generated by said selected one motor-generator so as to control a mechanical load of said selected one motor-generator on said engine. 
 
     
     
       14. The method of  claim 13  wherein controlling a level of electric current generated by said selected one motor-generator comprises controlling a current-controlling element connected with said selected one motor-generator. 
     
     
       15. The method of  claim 13  wherein said controlling a level of electric current generated by said selected one motor-generator comprises:
 sensing a user-selected vehicle speed control position; 
 determining from said control position whether the vehicle speed is to be increased or decreased; 
 decreasing said level of said electric current if said vehicle speed is to be increased; and 
 increasing said level of said electric current if said vehicle speed is to be decreased. 
 
     
     
       16. The method of  claim 15  wherein one of said increasing and decreasing corresponds to a change in said level of said electric current that is proportional to a difference between a recent user-selected control position and a previous user-selected control position. 
     
     
       17. The method of  claim 15  wherein one of said decrementing and incrementing corresponds to a change in said level of said electric current that is a predetermined fixed amount. 
     
     
       18. The method of  claim 13  wherein said high speed mode further comprises:
 when a user control position indicates a torque demand exceeding the capability of said engine, operating said selected one motor-generator in motor mode to propel said vehicle and supplement the power of said engine, and controlling current flow from said energy storage device to said selected one motor generator in accordance with changes in said user-selected control position. 
 
     
     
       19. The method of  claim 18  wherein said high speed mode further comprises:
 when a user control position indicates a torque demand exceeding the capability of the combination of said engine and said selected one motor-generator, operating the other one of said first and second motor-generators in motor mode to propel said vehicle by the combination of said engine, said first motor-generator and said second motor-generator, and controlling current flow from said energy storage device to said first and second motor generators in accordance with changes in said user-control position. 
 
     
     
       20. The method of  claim 13  further comprising operating said engine unthrottled.